The invention relates generally to a brush sealing system and a method for adjusting stiffness of a brush sealing system.
Efficiency of rotary machines utilized for pumping a fluid or compressing or expanding a vapor (e.g. gas) depends upon the internal tolerances of the components comprising the machine. A loosely-toleranced rotary machine may have a relatively poor fit between internal components and may therefore exhibit poor efficiency, with relatively high leakage occurring within the device from regions of higher pressure to regions of lower pressure. The traditional approach to this situation is to decrease the amount of clearance on these critical interfaces.
Sealing systems are used in rotary machines to reduce leakage of fluid flowing through the rotary machines. One or more seals extend along an interface between rotating and stationary components. One type of seal, referred to as a brush seal, uses a plurality of bristles held in place across the area to be sealed. One environment in which brush seals are commonly used is within gas turbine engines of the type used for providing propulsion to aircraft, auxiliary power to aircraft or other moving vessels, or in land based power generation embodiments. For example, the brush seal may be used between a gap formed between a stationary part such as a diffuser, engine casing, or stator, and a rotating part, such as a turbine blade, shaft, or rotor.
The manufacturing cycle for a brush seal typically occurs over several weeks. During the design process of a brush seal, various parameters are set with one example being a pinch point diameter of the brush seal. The pinch point diameter affects the seal's stiffness and heat generation capability. A pinch point diameter of a brush seal must be fixed during early stages of the design process of the brush seal because, if any design changes are requested during fabrication, the seal cannot readily be altered.
Accordingly, there is a need for a system and method that facilitates greater flexibility for adjusting a pinch point diameter of a brush seal during later stages of manufacturing and post manufacturing stages.